Polycyclic Aromatic Carbon Based Solid Strong Acid

ABSTRACT

A composite solid strong acid comprising, a solid acid and a carbon material, wherein said solid acid is obtained by heat treating of polycyclic aromatic hydrocarbons or polycyclic aromatic hydrocarbons to which the carbon material is blended in concentrated sulfuric acid or fuming sulfuric acid, transforming said polycyclic aromatic hydrocarbons to a solid acid which is insoluble in a polar solvent by condensation and sulfonation further compositing with said carbon material.

FIELD OF THE INVENTION

The present invention relates to a solid acid insoluble in a polarsolvent obtained by a process characterizing that polycyclic aromatichydrocarbon or polycyclic aromatic hydrocarbon to which carbon materialis blended is heat-treated in conc. sulfuric acid or in fuming sulfuricacid, then the polycyclic aromatic hydrocarbon is condensed andsulfonated, or composed with carbon materials which is blended at thecondensation or sulfonation reaction, or a composite solid strong acidcomposed by said solid acid and carbon material and an use of said solidacid as a solid strong acid catalyst.

DESCRIPTION OF THE PRIOR ART

Currently, energy situations or environmental situations are in criticalsituation, and it is required to produce only a subjected product aloneeffectively by small energy without producing unnecessary by-product.Acid catalyst is necessary for chemical industries of the present age,and used in production of various products such as chemicals, productsof petrochemical industry or polymer products, and considerable parts ofthe acid catalysts are a liquid acid such as hydrochloric acid orsulfuric acid. The liquid acid catalyst used in a production process isseparated from the product and recovered by means of processes ofneutralization with a base and removal of salt which is formed by theneutralization. However, energy consumed for the neutralization processand the removal process of salt occupies considerable parts in totalenergy used in all production processes. And the recovered salts areover supply in a market, further, since mostly of these salts areby-products whose utilizability is small, in many cases, treatment ofthese salts are difficult.

In such a circumstance, a solid acid does not need said neutralizationprocess or removing process of salt for separation and recovery, doesnot form unnecessary by-products and can produce an objected product bylower energy. Therefore, investigation was carried out in early stage(Ishihara, K; Hasegawa, A; Yamamoto, H. Angew. Chem. Int. Ed. 2001, 40,4077; Document 1). As the results of the investigation, a solid acidcatalyst such as zeolite, silica alumina or hydrous niobate obtains goodresults in chemical industries and provides good benefit to humansociety. Further, as a strong acid polymer, material prepared bysulfonation of polystyrene can be considered as a solid acid and hasbeen used as a cationic ion-exchange resin which indicates acidity for along time. Furthermore, Nafion (T.M. of Du-pont) which loads sulfonegroup on polytetrafuluoroethylene skeleton is known as a very strongsolid acid (solid super strong acid) having hydrophilicity, and it iswell known that these acid polymers act as a super strong acid havingacid strength stronger than liquid acid. However, polymer has problemsthat it is weak to heat and is too expensive for an industrial use.Accordingly, from the view points of performance and cost, it is verydifficult to design more advantageous industrial process by using solidacid catalyst than industrial process using liquid acid catalyst,therefore, almost all chemical industries depend on liquid acidcatalyst. Considering said circumstance, development of a solid acidcatalyst that exceeds a liquid acid catalyst from view points ofperformance and cost has been desired.

Further, as an inorganic type, although sulfuric acid trace zirconiaprepared by sulfuric acid treatment of zirconium oxide (ZrO₂) is a solidacid catalyst having the strongest acidity, the amount of sulfuric acidtrace is not so large, and numbers of acid point per unit weight issmaller than that of liquid acid, therefore, it is hard to satisfy saidrequirement.

The subject of the present invention is to provide a solid acid catalystwhich dissolves said problems and can be advantageously usable for anindustrial use. The inventors of the present invention think about astructure characterizing that sulfuric groups are loaded to a chemicalmaterial possessing a basic backbone which is stable against physicalaction such as heat, and pay attention to use a polycyclic hydrocarboncompounds characterizing that many aromatic compound rings, which arecontained in tar, pitch, fuel oil or asphalt, are condensed as acomposing material of said basic backbone. The inventors of the presentinvention use tar, pitch, fuel oil or asphalt itself or a polycyclichydrocarbon compounds characterizing that many aromatic compound ringsare condensed as a composing material of said basic backbone, heattreated them in concentrated sulfuric acid or fuming sulfuric acid, andthe chemical structural feature and acid characteristic of the obtainedproduct are investigated, and found out that condensation reaction ofthe composing material of said basic backbone is progressedsimultaneously with sulfonation and an useful material as a solid acidwhich can be used stable in high temperature condition can be obtained.Further, the inventors of the present invention carried outesterfication reaction of ethylalcohol and acetic acid by trial, andfind out that said reaction is remarkably accelerated by presence ofsaid solid acid and is useful as a solid acid catalyst, thus the subjectcan be accomplished. Further, in an investigation to obtain a solid acidmaterial which improves the characteristics of said obtained solid acid,carbon materials such as activated carbon or acetylene black are blendedto the material of said solid acid and heat treated in concentratedsulfuric acid or fuming sulfuric acid, and find out that a compositesolid acid of polycyclic aromatic carbon solid acid-carbon material canbe obtained.

SUMMARY OF THE INVENTION

The first one of the present invention is (1) a solid acid, which isinsoluble in a polar solvent, obtained by heat treating of polycyclicaromatic hydrocarbons in concentrated sulfuric acid or fuming sulfuricacid to thereby condense and sulfonate said polycyclic aromatichydrocarbons. Desirably, the first one of the present invention is (2)the solid acid of (1) wherein, the polycyclic aromatic hydrocarbons isat least one selected from the group consisting of a polycyclic aromatichydrocarbon obtained by condensing two or more aromatic rings, mixtureof a polycyclic aromatic hydrocarbon obtained by condensing two or morearomatic rings or tar, pitch, fuel oil or asphalt containing apolycyclic aromatic hydrocarbon obtained by condensing two or morearomatic rings, more desirably, the first one of the present inventionis (3) the solid acid of (1) or (2) wherein, temperature T for heattreatment is 100° C.≦T≦450° C., further desirably the first one of thepresent invention is (4) the solid acid of (3) wherein, the temperatureT for heat treatment is 200° C.≦T≦350° C.

The second one of the present invention is (5) a solid strong acidcatalyst comprising the solid acid of (1) which is insoluble in a polarsolvent. Desirably, the second one of the present invention is (6) thesolid strong acid catalyst comprising the solid acid of (2) which isinsoluble in a polar solvent, more desirably, the second one of thepresent invention is (7) the solid strong acid catalyst comprising thesolid acid of (2) which is insoluble in a polar solvent, furtherdesirably the second one of the present invention is (8) the solidstrong acid catalyst comprising the solid acid of (4) which is insolublein a polar solvent.

The third one of the present invention is (9) a composite solid strongacid comprising a solid acid and a carbon material, wherein said solidacid is obtained by heat treating of polycyclic aromatic hydrocarbons towhich the carbon material is blended in concentrated sulfuric acid orfuming sulfuric acid, transforming said polycyclic aromatic hydrocarbonsto a solid acid which is insoluble in a polar solvent by condensationand sulfonation further compositing with said carbon material.Desirably, the third one of the present invention is (10) the compositesolid strong acid of (9), wherein the aromatic hydrocarbons is at leastone selected from the group consisting of a polycyclic aromatichydrocarbon obtained by condensing two or more aromatic rings, mixtureof a polycyclic aromatic hydrocarbon obtained by condensing two or morearomatic rings or tar, pitch, fuel oil or asphalt containing apolycyclic aromatic hydrocarbon obtained by condensing two or morearomatic rings, more desirably, the third one of the present inventionis (11) the composite solid strong acid of (9) or (10), whereintemperature T for heat treatment is 100° C.≦T≦450° C., further desirablythe third one of the present invention is (12) the solid acid of (11)wherein, the temperature T for heat treatment is 200° C.≦T≦350° C.,furthermore desirably, the third one of the present invention is (13)the composite solid strong acid of (9), (10), (11) or (12), wherein, thecarbon material is at least one selected from the group consisting ofcarbon black, acetylene black, activated carbon, carbon nano tube orfullerene.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows catalytic activity of a solid acid obtained in Example 1when it is used as an acid catalyst for esterfication reaction ofethanol and acetic acid (● catalyst is existing, ▪ without catalyst.These marks are same in FIGS. 2-5).

FIG. 2 shows catalytic activity of a solid acid obtained in Example 2when it is used as an acid catalyst for esterfication reaction ofethanol and acetic acid.

FIG. 3 shows catalytic activity of a solid acid obtained in Example 3when it is used as an acid catalyst for esterfication reaction ofethanol and acetic acid.

FIG. 4 shows catalytic activity of a solid acid obtained in Example 4when it is used as an acid catalyst for esterfication reaction ofethanol and acetic acid.

FIG. 5 shows catalytic activity of a solid acid obtained in Example 5when it is used as an acid catalyst for esterfication reaction ofethanol and acetic acid.

FIG. 6 shows catalytic activity of a solid acid obtained in Example 6when it is used as an acid catalyst for esterfication reaction ofethanol and acetic acid (● shows activity of first time use and ◯ showsactivity of 2^(nd) time use. These marks are same in FIGS. 7-10).

FIG. 7 shows catalytic activity of a solid acid obtained in Example 7when it is used as an acid catalyst for esterfication reaction ofethanol and acetic acid.

FIG. 8 shows catalytic activity of a solid acid obtained in Example 8when it is used as an acid catalyst for esterfication reaction ofethanol and acetic acid.

FIG. 9 shows catalytic activity of a solid acid obtained in Example 9when it is used as an acid catalyst for esterfication reaction ofethanol and acetic acid.

FIG. 10 shows catalytic activity of a solid acid obtained in Example 10when it is used as an acid catalyst for esterfication reaction ofethanol and acetic acid.

FIG. 11 shows catalytic activity of an acid catalyst composed of SO₃Htype Nafion powder (product of Du pont) of Comparative Example 3 when itis used as an acid catalyst for esterfication reaction of ethanol andacetic acid.

FIG. 12 shows catalytic activity of an acid catalyst composed ofzirconia sulfate (product of Wako Junyaku) of Comparative Example 4 atfirst time use and 2^(nd) time use.

FIG. 13 shows catalytic activity of an activated carbon treated byconcentrated sulfuric acid (96%) of Comparative Example 5 when it isused as an acid catalyst for esterfication reaction of ethanol andacetic acid.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will be illustrated more in detail.

I. The acid catalyst of the present invention, which is insoluble in apolar solvent, can be obtained by heat treating of polycyclic aromatichydrocarbons contained in pitch, tar, fuel oil or asphalt inconcentrated sulfuric acid or fuming sulfuric acid, and condensationreaction of said polycyclic aromatic hydrocarbons is progressedsimultaneously with sulfonation reaction, therefore stabilized chemicalstructure is formed. Further, said solid acid indicates strong acidityand is useful as a solid strong acid catalyst and has a advantageousthat it can be synthesized by lower cost.

As an example of a polar solvent in which said solid acid is insoluble,water, alcohol, aldehyde, carboxylic acid, ketone, amine or imine can bementioned.

II. As a polycyclic aromatic hydrocarbons, compound characterized atleast two aromatic rings are condensed can be use as a starting materialfor synthesis of a solid acid of the present invention, however, whendegree of condensation is too small, time for synthesis of solid acidbecomes long, therefore, it is desirable to use a compound characterizedat least five aromatic rings are condensed as a starting material toobtain stable solid acid from the view point of industrial production.

It is well known that the polycyclic aromatic hydrocarbons arepolycondensed in concentrated sulfuric acid or fuming sulfuric acid andan amorphous material characterized that polycyclic aromatichydrocarbons are complexly polycondensed is formed, further, theproperty of it becomes closer to that of graphite along with theincrease of the numbers of aromatic rings.

The inventors of the present invention, predicts that polycyclicaromatic hydrocarbon characterized that many aromatic rings arecondensed forms the structure which progressed to two dimensional shapesimilar to graphite, and even if the outermost aromatic rings aresulfonated, it becomes a solid acid which is insoluble in water based onthe largely advanced structure of hydrophobic polycyclic aromatichydrocarbon, and tried heat treatment indicated by following formula 1.Formula 1 indicates a concept of the present invention in a case thatplural aromatic hydrocarbons are used as a starting material.

Said polycyclic aromatic hydrocarbon composed of naphthalene,anthracene, perylene or coronene is heat treated in concentratedsulfuric acid or fuming sulfuric acid and sulfonation andpolycondensation reactions are carried out. By said sulfonation andpolycondensation reactions, amorphous carbon material characterized thatmany sulfonated polycyclic aromatic hydrocarbons are condensed can beobtained.

When treating temperature in concentrated sulfuric acid or fumingsulfuric acid is lower than 100° C., since polycondensation of thepolycyclic aromatic hydrocarbon does not progress sufficiently and apolycyclic aromatic hydrocarbon composed of many aromatic rings is notformed, a solid acid which is insoluble in a polar solvent can not beobtained. On the contrary, when the treating temperature exceeds 450°C., insoluble amorphous hydro carbon in which sufficient amount ofsulfone group to occur heat decomposition of sulfone group is existing.

More desirable heat treatment temperature is 200-350° C. The solid acidcatalyst of the present invention can be synthesized not only bystarting material composed of single polycyclic aromatic hydrocarbon butalso by starting material composed of plural polycyclic aromatichydrocarbons. Further, the solid acid catalyst of the present inventioncan be synthesized using pitch, tar, fuel oil or asphalt in whichvarious polycyclic aromatic hydrocarbons, saturated hydrocarbon orunsaturated hydrocarbon are contained or mixture thereof as startingmaterials for synthesis.

III. As a carbon material used for the synthesis for a composite solidstrong acid by blending with starting materials for synthesis of saidpolycyclic aromatic hydrocarbons, carbon black, acetylene black,activated carbon (granular state, whisker state, pulp state), graphite,carbon nano tube or fullerene, which are characterized to hold formedsolid acid as a carrier for solid catalyst, desirably, a carbon materialhaving surface structure to the surface of which many sulfate roots canbe arranged, can be mentioned.

EXAMPLE

The present invention will be illustrated more specifically according tothe Examples, however, not intending to limit the scope of the presentinvention.

Measuring Apparatus;

A. Crystalline characteristic of synthesized solid acid catalyst ismeasured by an X-ray diffraction instrument, Geigerglex RAD-B, Cu Kα,product of Rigaku Co., Ltd.

B. Elementary analysis, sulfur content is measured using CHNS-932,product of LECO Co., Ltd., by burning a specimen under oxygen gas now.

C. Stability of sulfone group is measured by temperature-programmeddesorption (Multi Task TPD, product of Japan Bell Co., Ltd.) andthermogravimetric analysis (DTG-60/60H, product of Shimazu Co., Ltd.).

Example 1

1.00 g of coronene (C₂₄H₁₂) is added to 100 mL of conc. sulfuric acid(96%) and heated at 200° C. for 8 hours. Excess conc. sulfuric acid isremoved by vacuum distillation at 250° C., then black solid powder isobtained. This solid powder is washed by 300 mL of ethyl alcohol, andthe washing process is repeated until sulfuric acid contained in ethylalcohol after washed becomes under detection limit of elementaryanalysis. Since from X-ray diffraction pattern of the obtained blackpowder, any structure is not observed, this material is understood to beamorphous. From elementary analysis, sulfur content of this polycyclicaromatic carbon solid strong acid is 1.5 atm %, and presence of manysulfonic acid groups are detected. From the results oftemperature-programmed desorption and thermogravimetric analysis, it isconfirmed that the decomposition temperature of the polycyclic aromaticcarbon solid strong acid in atmosphere is 210° C., and is understoodthat thermo stability of it is high. Above mentioned black powder isevacuated at 150° C. for 1 hour, then 0.2 g of it is added as a catalystinto mixed solution of 0.1 mol acetic acid and 11.0 mol ethyl alcoholunder argon gas flow, stirred at 70° C. for 6 hours and the amount ofethyl acetate formed by acid catalyst reaction is detected by a gaschromatography. Results are shown in FIG. 1. In FIG. 1, for thecomparison, formation of ethyl acetate by reaction without catalyst isalso shown by time lapse. As shown in FIG. 1, forming speed of ethylacetate in the presence of synthesized catalyst is remarkably high, andit is understood that the synthesized material acts as a strong solidacid catalyst.

Example 2

1.00 g of coronene (C₂₄H₁₂) is added to 100 mL of conc. sulfuric acid(96%) and heated at 300° C. for 8 hours. Excess conc. sulfuric acid isremoved by vacuum distillation at 300° C., then black solid powder isobtained. This solid powder is washed by 300 mL of ethyl alcohol, andthe washing process is repeated until sulfuric acid contained in ethylalcohol after washed becomes under detection limit of elementaryanalysis. Since from X-ray diffraction pattern of the obtained blackpowder, any structure is not observed, this material is understood to beamorphous. From elementary analysis, sulfur content of this polycyclicaromatic carbon solid strong acid is 0.8 atm %, and presence of manysulfonic acid groups are detected. From the results oftemperature-programmed desorption and thermogravimetric analysis, it isconfirmed that the decomposition temperature of the polycyclic aromaticcarbon solid strong acid in atmosphere is 230° C., and is understoodthat thermo stability of it is high. Above mentioned black powder isevacuated at 150° C. for 1 hour, then 0.2 g of it is added as a catalystinto mixed solution of 11.0 mol acetic acid and 11.0 mol ethyl alcoholunder argon gas flow, stirred at 70° C. for 6 hours and the amount ofethyl acetate formed by acid catalyst reaction is detected by a gaschromatography. Results are shown in FIG. 2. In FIG. 2, for thecomparison, formation of ethyl acetate by reaction without catalyst isalso shown by time lapse. As shown in FIG. 2, forming speed of ethylacetate in the presence of synthesized catalyst is remarkably high, andit is understood that the synthesized material acts as a strong solidacid catalyst.

Example 3

0.50 g of coronene (C₂₄H₁₂) and 0.20 g of anthracene are added to 100 mLof conc. sulfuric acid (96%) and heated at 300° C. for 8 hours. Excessconc. sulfuric acid is removed by vacuum distillation at 300° C., thenblack solid powder is obtained. This solid powder is washed by 300 mL ofethyl alcohol, and the washing process is repeated until sulfuric acidcontained in ethyl alcohol after washed becomes under detection limit ofelementary analysis. Since from X-ray diffraction pattern of theobtained black powder, any structure is not observed, this material isunderstood to be amorphous. From elementary analysis, sulfur content ofthis polycyclic aromatic carbon solid strong acid is 4.5 atm %, andpresence of many sulfonic acid groups are detected. From the results oftemperature-programmed desorption and thermogravimetric analysis, it isconfirmed that the decomposition temperature of the polycyclic aromaticcarbon solid strong acid in atmosphere is 210° C., and is understoodthat thermo stability of it is high. Above mentioned black powder isevacuated at 150° C. for 1 hour, then 0.2 g of it is added as a catalystinto mixed solution of 0.1 mol acetic acid and 11.0 mol ethyl alcoholunder argon gas flow, stirred at 70° C. for 6 hours and the amount ofethyl acetate formed by acid catalyst reaction is detected by a gaschromatography. Results are shown in FIG. 3. In FIG. 3, for thecomparison, formation of ethyl acetate by reaction without catalyst isalso shown by time lapse. As shown in FIG. 3, forming speed of ethylacetate in the presence of synthesized catalyst is remarkably high, andit is understood that the synthesized material acts as a strong solidacid catalyst.

Example 4

1.00 g of coronene (C₂₄H₁₂) is poured into a flask with a refluxcondenser in which 20 mL of fuming sulfuric acid (SO₃:25%) is containedand refluxed at 150° C. for 2 hours. Excess conc. sulfuric acid isremoved by vacuum distillation at 250° C., then black solid powder isobtained. This solid powder is washed by 300 mL of ethyl alcohol, andthe washing process is repeated until sulfuric acid contained in ethylalcohol after washed becomes under detection limit of elementaryanalysis. Since from X-ray diffraction pattern of the obtained blackpowder, any structure is not observed, this material is understood to beamorphous. From elementary analysis using CHNS-932, which is a productof LECO Co., Ltd., USA, sulfur content of this polycyclic aromaticcarbon solid strong acid is 0.5 atm %, and presence of many sulfonicacid groups are detected. From the results of temperature-programmeddesorption and thermogravimetric analysis, it is confirmed that thedecomposition temperature of the polycyclic aromatic carbon solid strongacid in atmosphere is 210° C., and is understood that thermo stabilityof it is high. Above mentioned black powder is evacuated at 150° C. for1 hour, then 0.2 g of it is added as a catalyst into mixed solution of0.1 mol acetic acid and 1.0 mol ethyl alcohol under argon gas flow,stirred at 70° C. for 6 hours and the amount of ethyl acetate formed byacid catalyst reaction is detected by a gas chromatography. Results areshown in FIG. 4. In FIG. 4, for the comparison, formation of ethylacetate by reaction without catalyst is also shown by time lapse. Asshown in FIG. 4, forming speed of ethyl acetate in the presence ofsynthesized catalyst is remarkably high, and it is understood that thesynthesized material acts as a strong solid acid catalyst.

Example 5

2.00 g of petroleum pitch is added to 100 mL of conc. sulfuric acid(96%) and heated at 300° C. for 8 hours. Excess conc. sulfuric acid isremoved by vacuum distillation at 300° C., then black solid powder isobtained. This solid powder is washed by 300 mL of ethyl alcohol, andthe washing process is repeated until sulfuric acid contained in ethylalcohol after washed becomes under detection limit of elementaryanalysis. Since from X-ray diffraction pattern of the obtained blackpowder, any structure is not observed, this material is understood to beamorphous. From elementary analysis, sulfur content of this polycyclicaromatic carbon solid strong acid is 3.5 atm %, and presence of manysulfonic acid groups are detected. From the results oftemperature-programmed desorption and thermogravimetric analysis, it isconfirmed that the decomposition temperature of the polycyclic aromaticcarbon solid strong acid in atmosphere is 210° C., and is understoodthat thermo stability of it is high. Above mentioned black powder isevacuated at 150° C. for 1 hour, then 0.2 g of it is added as a catalystinto mixed solution of 0.1 mol acetic acid and 11.0 mol ethyl alcoholunder argon gas flow, stirred at 70° C. for 6 hours and the amount ofethyl acetate formed by acid catalyst reaction is detected by a gaschromatography. Results are shown in FIG. 5. In FIG. 5, for thecomparison, formation of ethyl acetate by reaction without catalyst isalso shown by time lapse. As shown in FIG. 5, forming speed of ethylacetate in the presence of synthesized catalyst is remarkably high, andit is understood that the synthesized material using petroleum pitch asa starting material acts as a strong solid acid catalyst.

Example 6

20 g of naphthalene is added to 300 mL of conc. sulfuric acid (96%) andheated at 250° C. for 15 hours. Excess conc. sulfuric acid is removed byvacuum distillation at 250° C., then black solid powder of polycyclicaromatic carbon solid strong acid is obtained. This polycyclic aromaticcarbon solid strong acid is washed by 300 mL of distilled water at 90°C., and the washing process is repeated until sulfuric acid contained inwater after washed becomes under detection limit of elementary analysis.From X-ray diffraction pattern of the obtained insulating polycyclicaromatic carbon solid strong acid any structure is not observed,therefore, this material is understood to be an amorphous material. Fromelementary analysis, sulfur content of this polycyclic aromatic carbonsolid strong acid is 7.1 atm %, and presence of many sulfonic acidgroups are detected. From the results of temperature-programmeddesorption and thermogravimetric analysis, it is confirmed that thedecomposition temperature of the polycyclic aromatic carbon solid strongacid in atmosphere is 250° C., and is understood that thermo stabilityof it is high.

Above mentioned polycyclic aromatic carbon solid strong acid isevacuated at 150° C. for 1 hour, then 0.2 g of it is added as a catalystinto mixed solution of 0.1 mol acetic acid and 10 mol ethyl alcoholunder argon gas flow, stirred at 70° C. for 6 hours and the amount ofethyl acetate formed by acid catalyst reaction is detected by a gaschromatography. Results are shown in FIG. 6 (a). In FIG. 6, for thecomparison, formation of ethyl acetate by reaction using same amount ofSO₃H Nafion as a catalyst is also shown by time lapse (b). As shown inthe Figure, in the presence of the synthesized catalyst, formation speedof ethyl acetate is very fast and it is understood that the synthesizedmaterial is a solid acid catalyst having stronger acid strength thanthat of Nafion (●). After reaction, recovered material is washed, thenused as a catalyst of same reaction. Results are shown in FIG. 6 (◯). Asclearly understood from FIG. 6, acid catalytic activity of polycyclicaromatic carbon solid strong acid does not deteriorate by repeating use.Further, said synthesized polycyclic aromatic carbon solid strong acidis heated with distilled water in an autoclave of 150° C. for 72 hoursand filtrated. This filtrated powder is evacuated for 1 hour at 150° C.,then 0.2 g of it is used as a catalyst and same reaction as mentionedabove is carried out. Catalytic activity of it is same as to the case ofFIG. 6. These results indicate that said polycyclic aromatic carbonsolid strong acid is chemically stable and acid strength of it is notdeteriorated even in hot water of 150° C.

Example 7

10 g of fuel oil (A fuel oil) is added to 300 mL of conc. sulfuric acid(96%) and heated at 250° C. for 15 hours. Excess conc. sulfuric acid isremoved by vacuum distillation at 250° C., and then black solid powderof polycyclic aromatic carbon solid strong acid is obtained. Thispolycyclic aromatic carbon solid strong acid is washed by 300 mL ofdistilled water at 90° C., and the washing process is repeated untilsulfuric acid contained in water after washed becomes under detectionlimit of elementary analysis. From X-ray diffraction pattern of theobtained insulating polycyclic aromatic carbon solid strong acid anystructure is not observed, therefore, this material is understood to bean amorphous material. From elementary analysis, sulfur content of thispolycyclic aromatic carbon solid strong acid is 8.5 atm %, and presenceof many sulfonic acid groups are detected. From the results oftemperature-programmed desorption and thermogravimetric analysis, it isconfirmed that the decomposition temperature of the polycyclic aromaticcarbon solid strong acid in atmosphere is 230° C., and is understoodthat thermo stability of it is high.

Above mentioned polycyclic aromatic carbon solid strong acid isevacuated at 150° C. for 1 hour, then 0.2 g of it is added as a catalystinto mixed solution of 0.1 mol acetic acid and 11.0 mol ethyl alcoholunder argon gas flow, stirred at 70° C. for 6 hours and the amount ofethyl acetate formed by acid catalyst reaction is detected by a gaschromatography. Results are shown in FIG. 7 (a). In FIG. 7, for thecomparison, formation of ethyl acetate by reaction using same amount ofSO₃H Nafion as a catalyst is also shown by time lapse (b). As shown inthe Figure, in the presence of the synthesized catalyst, formation speedof ethyl acetate is very fast and it is understood that the synthesizedmaterial is a solid acid catalyst having stronger acid strength thanthat of Nafion (●). After reaction, recovered material is washed, thenused as a catalyst of same reaction. Results are shown in FIG. 7 (◯). Asclearly understood from FIG. 7, acid catalytic activity of polycyclicaromatic carbon solid strong acid does not deteriorate by repeating use.Further, said synthesized polycyclic aromatic carbon solid strong acidis heated with distilled water in an autoclave of 150° C. for 72 hoursand filtrated. This filtrated powder is evacuated for 1 hour at 150° C.,then 0.2 g of it is used as a catalyst and same reaction as mentionedabove is carried out. Catalytic activity of it is same as to the case ofFIG. 7. These results indicate that said polycyclic aromatic carbonsolid strong acid is chemically stable and acid strength of it is notdeteriorated even in hot water of 150° C.

Example 8

5 g of asphalt is added to 300 mL of conc. sulfuric acid (96%) andheated at 250° C. for 15 hours. Excess conc. sulfuric acid is removed byvacuum distillation at 250° C., and then black solid powder ofpolycyclic aromatic carbon solid strong acid is obtained. Thispolycyclic aromatic carbon solid strong acid is washed by 300 mL ofdistilled water at 90° C., and the washing process is repeated untilsulfuric acid contained in water after washed becomes under detectionlimit of elementary analysis. From X-ray diffraction pattern of theobtained insulating polycyclic aromatic carbon solid strong acid anystructure is not observed, therefore, this material is understood to bean amorphous material. From elementary analysis, sulfur content of thispolycyclic aromatic carbon solid strong acid is 5.5 atm %, and presenceof many sulfonic acid groups are detected. From the results oftemperature-programmed desorption and thermogravimetric analysis, it isconfirmed that the decomposition temperature of the polycyclic aromaticcarbon solid strong acid in atmosphere is 280° C., and is understoodthat thermo stability of it is high.

Above mentioned polycyclic aromatic carbon solid strong acid isevacuated at 150° C. for 1 hour, then 0.2 g of it is added as a catalystinto mixed solution of 0.1 mol acetic acid and 11.0 mol ethyl alcoholunder argon gas flow, stirred at 70° C. for 6 hours and the amount ofethyl acetate formed by acid catalyst reaction is detected by a gaschromatography. Results are shown in FIG. 8 (a). In FIG. 8, for thecomparison, formation of ethyl acetate by reaction using same amount ofSO₃H Nafion as a catalyst is also shown by time lapse (b). As shown inthe Figure, in the presence of the synthesized catalyst, formation speedof ethyl acetate is very fast and it is understood that the synthesizedmaterial is a solid acid catalyst having stronger acid strength thanthat of Nafion (●). After reaction, recovered material is washed, thenused as a catalyst of same reaction. Results are shown in FIG. 8 (◯). Asclearly understood from FIG. 8, acid catalytic activity of polycyclicaromatic carbon solid strong acid does not deteriorate by repeating use.Further, said synthesized polycyclic aromatic carbon solid strong acidis heated with distilled water in an autoclave of 150° C. for 72 hoursand filtrated. This filtrated powder is evacuated for 1 hour at 150° C.,then 0.2 g of it is used as a catalyst and same reaction as mentionedabove is carried out. Catalytic activity of it is same as to the case ofFIG. 8. These results indicate that said polycyclic aromatic carbonsolid strong acid is chemically stable and acid strength of it is notdeteriorated even in hot water of 150° C.

Example 9

Polycyclic aromatic carbon solid strong acid-carbon material composite 5g of naphthalene and 5 g of activated carbon are added to 300 mL ofconc. sulfuric acid (96%) and heated at 250° C. for 15 hours. Excessconc. sulfuric acid is removed by vacuum distillation at 250° C., andthen black solid powder of polycyclic aromatic carbon solid strongacid-carbon material composite is obtained. This aromatic carbon solidstrong acid-carbon material composite is washed by 300 mL of distilledwater at 90° C., and the washing process is repeated until sulfuric acidcontained in water after washed becomes under detection limit ofelementary analysis. From elementary analysis, sulfur content of thispolycyclic aromatic carbon solid strong acid is 3.5 atm %, and presenceof many sulfonic acid groups are detected. From the results oftemperature-programmed desorption and thermogravimetric analysis, it isconfirmed that the decomposition temperature of the polycyclic aromaticcarbon solid strong acid-carbon material composite in atmosphere is 230°C., and is understood that thermo stability of it is high.

Above mentioned polycyclic aromatic carbon solid strong acid-carbonmaterial composite is evacuated at 150° C. for 1 hour, then 0.2 g of itis added as a catalyst into mixed solution of 0.1 mol acetic acid and11.0 mol ethyl alcohol under argon gas flow, stirred at 70° C. for 6hours and the amount of ethyl acetate formed by acid catalyst reactionis detected by a gas chromatography. Results are shown in FIG. 9 (a). InFIG. 9, for the comparison, formation of ethyl acetate by reaction usingsame amount of SO₃H Nafion as a catalyst is also shown by time lapse(b). As shown in the Figure, in the presence of the synthesizedcatalyst, formation speed of ethyl acetate is very fast and it isunderstood that the synthesized material is a solid acid catalyst havingstronger acid strength than that of Nafion (●). Further, it is confirmedthat the obtained polycyclic aromatic carbon solid strong acid-carbonmaterial composite indicates stronger activity than that of polycyclicaromatic carbon solid strong acid whose starting material is naphthalenealone, and it is also confirmed that acid catalytic activity can beimproved by adhering polycyclic aromatic carbon solid strong acid to thesurface of activated carbon having broad surface area. After reaction,recovered material is washed, then used as a catalyst of same reaction.Results are shown in FIG. 9 (◯). As clearly understood from FIG. 9, acidcatalytic activity of polycyclic aromatic carbon solid strongacid-carbon material composite does not deteriorate by repeating use.Further, said synthesized polycyclic aromatic carbon solid strongacid-carbon material composite is heated with distilled water in anautoclave of 150° C. for 72 hours and filtrated. This filtrated powderis evacuated for 1 hour at 150° C., then 0.2 g of it is used as acatalyst and same reaction as mentioned above is carried out. Catalyticactivity of it is same as to the case of FIG. 9. These results indicatethat said polycyclic aromatic carbon solid strong acid-carbon materialcomposite is chemically stable and acid strength of it is notdeteriorated even in hot water of 150° C.

Example 10

5 g of naphthalene and 5 g of acetylene black are added to 300 mL ofconc. sulfuric acid (96%) and heated at 250° C. for 15 hours. Excessconc. sulfuric acid is removed by vacuum distillation at 250° C., andthen black solid powder of polycyclic aromatic carbon solid strongacid-carbon material composite is obtained. This aromatic carbon solidstrong acid-carbon material composite is washed by 300 mL of distilledwater at 90° C., and the washing process is repeated until sulfuric acidcontained in water after washed becomes under detection limit ofelementary analysis. From elementary analysis, sulfur content of thispolycyclic aromatic carbon solid strong acid is 4.7 atm %, and presenceof many sulfonic acid groups are detected. From the results oftemperature-programmed desorption and thermogravimetric analysis, it isconfirmed that the decomposition temperature of the polycyclic aromaticcarbon solid strong acid-carbon material composite in atmosphere is 230°C., and is understood that thermo stability of it is high.

Above mentioned polycyclic aromatic carbon solid strong acid-carbonmaterial composite is evacuated at 150° C. for 1 hour, then 0.2 g of itis added as a catalyst into mixed solution of 0.1 mol acetic acid and11.0 mol ethyl alcohol under argon gas flow, stirred at 70° C. for 6hours and the amount of ethyl acetate formed by acid catalyst reactionis detected by a gas chromatography. Results are shown in FIG. 10 (a).In FIG. 10, for the comparison, formation of ethyl acetate by reactionusing same amount of SO₃H Nafion as a catalyst is also shown by timelapse (b). As shown in the Figure, in the presence of the synthesizedcatalyst, formation speed of ethyl acetate is very fast and it isunderstood that the synthesized material is a solid acid catalyst havingstronger acid strength than that of Nafion (●). Further, it is confirmedthat the obtained polycyclic aromatic carbon solid strong acid-carbonmaterial composite indicates stronger activity than that of polycyclicaromatic carbon solid strong acid whose starting material is naphthalenealone, and it is also confirmed that acid catalytic activity can beimproved by adhering polycyclic aromatic carbon solid strong acid to thesurface of acetylene black having broad surface area.

After reaction, recovered material is washed, and then used as acatalyst of same reaction. Results are shown in FIG. 10 (◯). As clearlyunderstood from FIG. 10, acid catalytic activity of polycyclic aromaticcarbon solid strong acid-carbon material composite does not deteriorateby repeating use. Further, said synthesized polycyclic aromatic carbonsolid strong acid-carbon material composite is heated with distilledwater in an autoclave of 150° C. for 72 hours and filtrated. Thisfiltrated powder is evacuated for 1 hour at 150° C., then 0.2 g of it isused as a catalyst and same reaction as mentioned above is carried out.Catalytic activity of it is same as to the case of FIG. 10. Theseresults indicate that said polycyclic aromatic carbon solid strongacid-carbon material composite is chemically stable and acid strength ofit is not deteriorated even in hot water of 150° C.

Comparative Example 1

1.00 g of coronene (C₂₄H₁₂) is added to 100 mL of conc. sulfuric acid(96%) and heated at 50° C. for 8 hours, then centrifuged by 3000 rpmrotating speed for 30 minutes, however solid is not separated. It isconsidered that by the temperature condition of 50° C., polycondensationof aromatic rings is not sufficient and sulfonated polycyclic aromaticcarbon solid strong acid can not be existed as an insoluble solid.

Comparative Example 2

1.00 g of coronene (C₂₄H₁₂) is added to 100 mL of conc. sulfuric acid(96%) and heated at 500° C. for 2 hours, and black solid powder isobtained. This solid powder is washed by 300 mL of ethyl alcohol, andthe washing process is repeated until sulfuric acid contained in ethylalcohol after washed becomes under detection limit of elementaryanalysis. Since from X-ray diffraction pattern of the obtained blackpowder, any structure is not observed, this material is understood to beamorphous. From elementary analysis, sulfur content of this polycyclicaromatic carbon solid strong acid is 0.05 atm %. Above mentioned blackpowder is evacuated at 150° C. for 1 hour, then 0.2 g of it is added asa catalyst into mixed solution of 0.1 mol acetic acid and 11.0 mol ethylalcohol under argon gas flow, stirred at 70° C. for 6 hours and theamount of ethyl acetate formed by acid catalyst reaction is detected bya gas chromatography. The forming speed of ethyl acetate is not so muchdifferent from the state of without catalyst and is clearly understoodthat the synthesized material does not act as a solid acid catalyst. Forthe quantitative analysis of sulfur amount loaded to the surface, X-rayphotoelectron spectroscopic spectrum of said black powder is measured,and from the result it become clear that sulfur is not exist on thesurface. The reason why is considered as follows, that is, whentemperature for treatment is too high, sulfone groups on surface aredecomposed.

Comparative Example 3

Proton exchanged SO₃H Nafion powder (product of Du'pont) is evacuated at150° C. for 1 hour, then 0.2 g of it is added as a catalyst into mixedsolution of 0.1 mol acetic acid and 1.0 mol ethyl alcohol under argongas flow, stirred at 70° C. for 6 hours and the amount of ethyl acetateformed by acid catalyst reaction is detected by a gas chromatography.Results are shown in FIG. 11 (a). Formation of ethyl acetate isprogressed under the presence of Nafion. After reaction, recoveredmaterial is washed, and then used as a catalyst of same reaction.Results are shown in FIG. 11. As clearly understood from FIG. 11, acidcatalytic activity of Nafion does not deteriorate by repeating use.Further, said synthesized polycyclic aromatic carbon solid strong acidis heated with distilled water in an autoclave of 150° C. for 72 hoursand filtrated. This filtrated powder is evacuated for 1 hour at 150° C.,then 0.2 g of it is used as a catalyst and same reaction as mentionedabove is carried out. As shown in FIG. 11, catalytic activity of it isremarkably deteriorated (b). These results indicates that the stabilityof Nafion is lower than that of said polycyclic aromatic carbon solidstrong acid-carbon material composite and acid strength of Nafiondeteriorate in water of 150° C.

Comparative Example 4

Zirconia sulfate (product of Wako Junyaku Co., Ltd.) is evacuated at150° C. for 1 hour, then 0.2 g of it is added as a catalyst into mixedsolution of 0.1 mol acetic acid and 11.0 mol ethyl alcohol under argongas flow, stirred at 70° C. for 6 hours and the amount of ethyl acetateformed by acid catalyst reaction is detected by a gas chromatography.Results are shown in FIG. 12. Formation of ethyl acetate is progressedunder the presence of zirconia sulfate (●). After reaction, recoveredmaterial is washed, and then used as a catalyst of same reaction.Results are shown in FIG. 12 (◯). As clearly understood by the Figure,acid catalytic activity of zirconia sulfate remarkably deteriorated byrepeating use, and sulfuric acid trace on the surface of zirconiasulfate is unstable in water.

Comparative Example 5

5 g of activated carbon is added to 300 mL of conc. sulfuric acid (96%)and heated at 250° C. for 15 hours. Excess conc. sulfuric acid isremoved by vacuum distillation at 250° C., and then black powder isobtained. This black powder is washed by 300 mL of distilled water at90° C., and the washing process is repeated until sulfuric acidcontained in water after washed becomes under detection limit ofelementary analysis. From elementary analysis, sulfur content of thispolycyclic aromatic carbon solid strong acid-carbon material compositeis confirmed to be smaller than 0.05 atm %. X-ray diffraction pattern ofthe obtained black powder is same as X-ray diffraction pattern of theactivated carbon before heat treatment in conc. sulfuric acid.

Above mentioned black powder is evacuated at 150° C. for 1 hour, then0.2 g of it is added as a catalyst into mixed solution of 0.1 mol aceticacid and 11.0 mol ethyl alcohol under argon gas flow, stirred at 70° C.for 6 hours and the amount of ethyl acetate formed by acid catalystreaction is detected by a gas chromatography. Results are shown in FIG.13. Clearly understood from the Figure, forming speed of ethyl acetateis slow under the presence of synthesized catalyst, and is confirmedthat acid catalytic function of the synthesized material is very small.

INDUSTRIAL APPLICABILITY

Solid strong acid or solid strong acid-carbon material composite of thepresent invention which are insoluble in a polar solvent is a materialhaving strong acid characteristic produced by relatively easy methodusing cheap material, therefore, brings an excellent effect that areadvantageous from view points of cost, function and industry.

1. A solid acid, which is insoluble in a polar solvent, obtained by heattreating of polycyclic aromatic hydrocarbons in concentrated sulfuricacid or fuming sulfuric acid to thereby condense and sulfonate saidpolycyclic aromatic hydrocarbons.
 2. The solid acid of claim 1, whereinpolycyclic aromatic hydrocarbons is at least one selected from the groupconsisting of a polycyclic aromatic hydrocarbon obtained by condensingtwo or more aromatic rings, mixture of a polycyclic aromatic hydrocarbonobtained by condensing two or more aromatic rings or tar, pitch, fueloil or asphalt containing a polycyclic aromatic hydrocarbon obtained bycondensing two or more aromatic rings.
 3. The solid acid of claim 1 orclaim 2, wherein temperature T for heat treatment is 100° C.≦T≦450° C.4. The solid acid of claim 3, wherein temperature T for heat treatmentis 200° C.≦T≦350° C.
 5. A solid strong acid catalyst comprising, a solidacid, which is insoluble in a polar solvent, obtained by heat treatingof polycyclic aromatic hydrocarbons in concentrated sulfuric acid orfuming sulfuric acid to thereby to concentrate and sulfonate saidpolycyclic aromatic hydrocarbons.
 6. The solid strong acid catalyst ofclaim 5, wherein polycyclic aromatic hydrocarbons is at least oneselected from the group consisting of a polycyclic aromatic hydrocarbonobtained by condensing two or more aromatic rings, mixture of apolycyclic aromatic hydrocarbon obtained by condensing two or morearomatic rings or tar, pitch, fuel oil or asphalt containing apolycyclic aromatic hydrocarbon obtained by condensing two or morearomatic rings.
 7. The solid strong acid catalyst of claim 5 or claim 6,wherein temperature T for heat treatment is 100° C.≦T≦450° C.
 8. Thesolid strong acid catalyst of claim 7, wherein temperature T for heattreatment is 200° C.≦T≦350° C.
 9. A composite solid strong acidcomprising, a solid acid and a carbon material, wherein said solid acidis obtained by heat treating of polycyclic aromatic hydrocarbons towhich the carbon material is blended in concentrated sulfuric acid orfuming sulfuric acid, transforming said polycyclic aromatic hydrocarbonsto a solid acid which is insoluble in a polar solvent by condensationand sulfonation further compositing with said carbon material.
 10. Thecomposite solid strong acid of claim 9, wherein polycyclic aromatichydrocarbons is at least one selected from the group consisting of apolycyclic aromatic hydrocarbon obtained by condensing two or morearomatic rings, mixture of a polycyclic aromatic hydrocarbon obtained bycondensing two or more aromatic rings or tar, pitch, fuel oil or asphaltcontaining a polycyclic aromatic hydrocarbon obtained by condensing twoor more aromatic rings.
 11. The composite solid strong acid of claim 9or claim 10, wherein temperature T for heat treatment is 100° C.≦T≦450°C.
 12. The composite solid strong acid of claim 11, wherein temperatureT for heat treatment is 200° C.≦T≦350° C.
 13. The composite solid strongacid according to any one of claims 9, 10, 11 or 12, wherein the carbonmaterial is at least one selected from the group consisting of carbonblack, acetylene black, activated carbon, carbon nano tube or fullerene.